Changing the Outgoing DNS (port 53) IP address with Iptables?

[lazyhat]

Hey there, I need to know what the Iptables "code" is to change the outgoing/Incoming IP for port 53 (DNS). I'm running CentOS on a dedicated server. I very familiar with Putty and SSH. So I don't need much details, I just can't figure this out. I asked my server providor but they deleted my ticket and didn't answer me.

I tried this but am not sure if this correct of working?

iptables -t nat -A POSTROUTING -o eth0 -p tcp --dport 53 -j SNAT --to xx.xx.xx.xx

Any help on this would be great! Thanks.

[Lazydog]

OK, why are you trying to change the ip address of the leaving packet?

[lazyhat]

OK, why are you trying to change the ip address of the leaving packet?

Our names are similar


Well I have to work around a block. See I run a these things called anonymous proxy sites and Facebook has kindly blocked my server from getting its DNS. So none of my users can access the site threw a cURL proxy script, I get "Namelookup timeout".

I need to change to my DNS IP. I have like 30 IPs on my server.

[Lazydog]

Post the output from the following command

dig facebook.com

[lazyhat]

I never knew that Dig thing.. Interesting. Its actually not Facebook I can't connect to its login.facebook.com . cURL returns. "namelookup timeout". But doing a Dig on that it does return the DNS. I really dont get this. I think there might some fatal error in the cURL gets DNS?






;

;
;; Query time: 0 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Wed Apr  1 15:39:03 2009
;; MSG SIZE  rcvd: 232

root@server [~]# dig login.facebook.com

; <<>> DiG 9.3.4-P1 <<>> login.facebook.com
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 40015
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 3, ADDITIONAL: 3

;; QUESTION SECTION:
;login.facebook.com.            IN      A

;; ANSWER SECTION:
login.facebook.com.     30      IN      A       69.63.180.173

;; AUTHORITY SECTION:
login.facebook.com.     718     IN      NS      glb01.ams1.tfbnw.net.
login.facebook.com.     718     IN      NS      glb01.ash1.tfbnw.net.
login.facebook.com.     718     IN      NS      glb01.sf2p.tfbnw.net.

;; ADDITIONAL SECTION:
glb01.ams1.tfbnw.net.   5759    IN      A       69.63.191.219
glb01.ash1.tfbnw.net.   5759    IN      A       69.63.185.11
glb01.sf2p.tfbnw.net.   5759    IN      A       69.63.176.101

;; Query time: 38 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Wed Apr  1 15:39:22 2009
;; MSG SIZE  rcvd: 184

[Lazydog]

Yes, this shows that DNS is working.